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Coral disease is a major cause of coral reef degradation, yet many diseases remain understudied. Yellow-banded tissue loss disease (YBTLD) has a distinct gross lesion morphology and to date has only been reported from the Arabian/Persian Gulf; little else is known about the ecology of the disease. We report on the first occurrence of YBTLD outside of the Arabian/Persian Gulf at 2 sites (Laku Point, Narara Reef) within the Gulf of Kachchh (GoK) located on the northwest coast of India. At Narara Reef, YBTLD was observed at 12 out of 24 transects with an average prevalence of 4.7 ± 1.3%. At Laku Point, YBTLD was observed at 19 out of 24 transects with an average prevalence of 5.4 ± 1%. Four out of 15 coral genera within transects had signs of YBTLD and included Goniopora, Dipsastraea, Lobophyllia, and Turbinaria. Lobophyllia and Turbinaria had the highest susceptibility to the disease, with prevalence significantly higher than expected based on their abundance on the reefs. The distribution and prevalence of YBTLD in the GoK was higher than in coral reefs in the Arabian/Persian Gulf. The GoK is an extreme environment for coral reefs with both natural stressors (high salinities, strong, seasonal storm activities, and extreme tides) and anthropogenic pollutants from industrial, mining, agricultural, and domestic activities. These poor environmental conditions may help explain the high occurrence of YBTLD on GoK reefs.

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The port-based activity is often associated with industrial growth in the hinterland and similar phenomenon reported from the Gulf of Kachchh, India. Industrialization exerts pressure on coastal water through the release of waste water or effluents which influence the entire marine ecosystem. The present paper tries to evaluate the variation in the water quality during the high tide and low tide in relation to the anthropogenic or natural influence in Gulf of Kachchh. The tidal variation is important as it reflects the influence of the land-based activity on the coastal waters. To prove this logic, a series of stations were taken along the coastal water and statistical analysis, viz., Pearson correlation, Box plot, hierarchical cluster analysis (HCA), and factor analysis (PCA/FA) were conducted. Pearson correlation and Box plot represent visual impact of parameter variations in respected tides. The chemometric analysis, i.e., HCA and PCA/FA, clearly indicates an anthropogenic impact on coastal water. The results of HCA revealed that major anthropogenic and domestic impacts were found at various stations during the low tide. The HCA points out that an anthropogenic and the tidal activity in the Gulf of Kachchh influence the physical water quality parameters like pH, salinity, dissolved solid, oxygen, turbidity, sulfate, and nutrients in the coastal ecosystem. The PCA/FA further ascertains the finding of HCA analysis that the state of the art of the water quality of coastal ecosystem has direct relevance with the land-based activities and sewage outfall points. Tide-based control on the water quality parameters was evident that the high tide nutrients like phosphates and nitrogen were high, while during the low tide, temperature, salinity, total solids, and sulfate showed higher concentrations. The findings of the paper will be useful for developing effective management strategies for policy makers or stakeholders operating in the coastal area.

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Coral reefs are constantly subjected to multiple stresses like diseases and fish predation, which can profoundly influence the coral microbiome. This study investigated the differences in bacterial community structure of healthy, white syndrome affected and blenny nipped coral colonies of Porites lutea, collected from the coral reefs of Gulf of Kachchh, north-west coast of India. Present study observed that the stressed coral colonies harbored more OTUs and contained higher diversity values compared to healthy corals colonies. Similarly, beta diversity analysis indicated the dissimilarities among the three coral samples analyzed. Though the taxonomy analysis indicated bacterial phyla like Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria among the entire coral samples studied, there was a variation in their relative abundances. Huge variations were observed in the relative dominance at the bacterial genera level. About 13phyla and 11 genera was identified in healthy coral. The PBN sample was found to contain Proteobacteria, Cyanobacteria, Verrucomicrobia, and Lentisphaerae as dominant phyla and Endozoicomonas, Dyella, Woeseia, and Winogradskyella as dominant genera. The PWS sample contained Proteobacteria, Lentisphaerae, Spirochaetes, and Tenericutes as dominant phyla and Endozoicomonas, Arcobacter, Sunxiuqinia, and Carboxylicivirgia as dominant genera. Among the healthy samples, sequences belonging to Uncultured Rhodospirillaceae were dominant, while Woeseia and sequences belonging to Uncultured Rhodovibrionaceae were dominant among the blenny nipped white syndrome infected corals. Although any previously established pathogen was not identified, present study revealed the presence of a potentially pathogenic bacterium, Arcobacter, among the diseased corals. It also demonstrated a dynamic microbiome among the Porites lutea colonies on subjecting to various stresses.

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The marine ecosystem contains a solution for food, shelter, pharmaceutical problems and has a key role in the economy of the country as tourism. The Gulf of Kachchh, known for its high tides and the coral reefs are less explored for its antibiotic activity due to the coral bleaching and diseases. The bacterial strains in the coral Porites lutea are determined to possess antibiotic activity against bacterial strains such as E.coli, P. aeruginosa, S. aureus and S. faecalis. Among thirty bacterial strains isolated from the tissue, skeleton and mucus, two bacterial strains resulted in the better antagonistic activity. The antibiotic compound extracted from both the bacteria elucidated to be 4-[(2E)-4-hydroxypent-2-en-1-yl]-5,6-dihydro-2H-pyran-2-one. Further, through ADMET prediction it was inferred that it is an effective drug lead as it reports less toxicity and better drug-likeliness. The study also includes the effect of Poly Hydroxy Butarate (PHB) production by the isolated bacterial strain.

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The present study is aimed at investigation of surface water quality of Gulf of Kachchh (GoK), Gujarat. The main objective of this study was to convert complex dataset of water quality parameters from GoK into comprehensive, simple and interpretable observations. Hence, physico-chemical parameters and nutrients of surface water from GoK were analyzed. Chemometric results indicated that oxygen, salinity, dissolved solids, nutrient and natural conditions were the factors that affected surface water quality. The water quality index was calculated to identify water quality classes to evaluate the spatio-seasonal trend in the study area. The results revealed that water quality was moderate in summer, worst in pre-monsoon and best in post-monsoon. The study also highlighted that Marine National Park (Central GoK) was observed to be comparatively in good condition with abundant marine biodiversity. Thus, the results of chemometric study of water quality parameters can be a valuable tool for government authorities for sustainable development of GoK.

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The identity of Arcotheres placunae (Hornell Southwell, 1909) (Pinnotheridae), a pea crab associated with the window pane shell, Placuna placenta, has been confused as the types are lost and the original figures are inaccurate and do not match the description given of the species. In the present study, fresh specimens of the species were collected from the type locality (Gulf of Kachchh, Gujarat, India), and the species is here redescribed and refigured, and its affinities with similar species is discussed. To stabilize the taxonomy of A. placunae, a neotype is chosen from amongst the fresh material.

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Coral reefs are often termed underwater wonderlands due to the presence of an incredible biodiversity including numerous invertebrates and vertebrates. Among the dense population of benthic and bottom-dwelling inhabitants of the reef, many significant species remain hidden or neglected by researchers. One such example is the vermetids, a unique group of marine gastropods. The present study attempts for the first time to assess the density and identify preferred reef substrates in the Gulf of Kachchh, state of Gujarat, on the western coast of India. A total of three species of the family Vermetidae were recorded during the study and their substrate preferences identified.